Fingerprint sensing and matching is a reliable and widely used technique for personal identification or verification. In particular, a common approach to fingerprint identification involves scanning a sample fingerprint or an image thereof and storing the image and/or unique characteristics of the fingerprint image. The characteristics of a sample fingerprint may be compared to information for reference fingerprints already in a database to determine proper identification of a person, such as for verification purposes.
A particularly advantageous approach to fingerprint sensing is disclosed in U.S. Pat. No. 5,953,679 to Setlak et al. and assigned to the assignee of the present invention. The fingerprint sensor is an integrated circuit sensor that drives the user's finger with an electric field signal and senses the electric field with an array of electric field sensing pixels on the integrated circuit substrate. Such sensors are used to control access for many different types of electronic devices such as computers, cell phones, personal digital assistants (PDA's), and the like. In particular, fingerprint sensors are used because they may have a small footprint, are relatively easy for a user to use, and they provide reasonable authentication capabilities.
U.S. Published Patent Application No. 2005/0089203 also to Setlak and assigned to the assignee of the present invention discloses an integrated circuit biometric sensor that may sense multiple biometrics of the user, and that is also adapted to either a static placement sensor or a slide finger sensor. A slide finger sensor includes a smaller sensing surface over which the user's finger is slid. The images collected during the sliding process may be collected for matching, such as for authentication, or may be used for navigation, for example.
U.S. Published Patent Application No. 2001/0025342 to Uchida is directed to a biometric identification method and system where the system has a biometric input device and a separately provided biometric verifier. The biometric data input device has a biometric data sensor and an encoder that encodes digital biometric data using secret information identifying the biometric data input device to transmit encoded data to the biometric verifier. The biometric verifier decodes the encoded data using the secret information to reproduce digital biometric data. The system and method include the use of digital watermarking and/or encryption of data that is then transmitted to the verifier for decryption and decoding.
Some conventional fingerprint security systems, simply return an index indicating which template matched a live sample. An application running on a host computer would then retrieve security material from its own storage based on this answer. A shortcoming with this approach is that it is possible for a hacker to replace the software and hardware stack with a simple Dynamic-link library (DLL), for example, that just always returns a valid index number regardless of what finger is presented. In fact, no finger need be present at all. Accordingly, even if the application and the software cross-authenticate, there is still a single, locatable, point of attack where malicious software can change the returned answer to anything desired.
UPEK, Inc. of Emeryville, Calif. offers a TouchStrip® Fingerprint Authentication Module (TCED) that is a complete biometric subsystem based on its TCS3 sensor and TCD42 digital identification engine. Everything is mounted on a compact PCB including a USB-ready flex cable connector to simplify integration and speed time to market. Unfortunately, this so-called two-chip finger sensing approach may be relatively expensive compared to other approaches.
There are approaches to finger sensing that may have security issue that may be exploited. In addition, some existing finger sensing approaches, such as those requiring two dedicated chips, may be relatively expensive to implement.